The gunman who livestreamed himself opening fire on a Christchurch mosque, turned the camera on himself before carrying out his deadly attack.

He described his reasons for the disgusting attack as to "show the invaders that our lands will never be their lands, our homelands are our own and that, as long as a white man still lives, they will NEVER conquer our lands and they will never replace our people".

Tarrant revealed he had been planning an attack for up to two years, noting he decided on Christchurch three months ago.

He said New Zealand was not the "original choice for attack", but described it as "target rich of an environment as anywhere else in the West".

"An attack in New Zealand would bring to attention the truth of the assault on our civilisation, that no where (sic) in the world was safe, the invaders were in all of our lands, even in the remotest areas of the world and that tehre was no where (sic) left to go that was safe and free from mass immigration."

Claiming to represent "millions of European and other ethno-nationalist peoples", he said "we must ensure the existence of our people, and a future for white children".

The gunman described the attack as an act of "revenge on the invaders for the hundreds of thousands of death caused by foreign invaders in European lands throughout history … for the enslavement of millions of Europeans taken from their lands by the Islamic slavers … (and) for the thousands of European lives lost to terror attacks throughout European lands."

He also said it was to take revenge for Ebba Akerlund, the 11-year-old child who was killed in a 2017 terror attack in Stockholm.

Further down in the manifesto, Tarrant described the Stockholm attack as the "first event" that inspired him to commit the attack, particularly the death of the 11-year-old girl.

"Ebba (sic) death at the ahdns of the invaders, the indignity of her violent demise and my inability to stop it broke through my own jaded cynicism like a sledgehammer. I could no longer ignore the attacks."

Ebba Akerlund, 11, was killed in a truck attack in Stockholm in 2017.

He said the attack was also inspired by a trip he took to France in 2017. "For many years I had been hearing and reading of the invasion of France by non-whites, many of these rumours and stories I believed to be exaggerations, created to push a political narrative.

"But once I arrived in France, I found the stories not only be true, but profoundly understated. In every french city, in every french town the invaders were there."

Earlier in the manifesto, Tarrant described his childhood as "regular" and "without any great issues", noting he had little interest in his education and "barely achieved a passing grade" at school. He said he earned money investing in Bitconnect, an open-source cryptocurrency.

Tarrant said he feels no remorse for the attack. "I only wish I could have killed more invaders, and more traitors as well." He also said there "was a racial component to the attack" and described it as "anti-immigration" and "an attack in the name of diversity".

He also said he will plead not guilty if he survives and goes to trial.

Posting on an 8chan forum, a user who identified himself as Tarrant announced he would carry out the attack.

"I will carry out and attack against the invaders, and will even live stream the attack via facebook," he wrote, with a link to his Facebook page. "If I don't survive the attack, goodbye, godbless and I will see you all in Valhalla!"

Many anonymous users responded praising him for the attack, with comments like "Godspeed" and "that video is so goddamn good".

People in the 8chan forum praised the gunman’s post.

In the days leading up to the attack, Tarrant posted photos to his now-suspended Twitter account of what appears to be guns, ammunition and a military-style vest.

The weaponry is scrawled with references to ancient battles and more recent attacks against Muslims.

Tarrant posted photos to his now-suspended Twitter account of what appears to be guns, ammunition and a military-style vest.

The weaponry is scrawled with references to ancient battles and more recent attacks against Muslims.

Bissonnette was sentenced to 40 years for shooting six people dead in the 2017 shooting at a mosque in Quebec.

Traini, an Italian man, is serving 12 years in prison for the shooting of six African migrants in a racially motivated attack in October last year.

On what appears to be a gun, the message "Here's your migration compact!" is written.

The writing also cites military leaders and refers to ancient battles such as the 1189 Siege of Acre and Ottoman Empire battles including the 1863 battle of Vienna and the 1877 battle of Shipka Pass.

The writing names Feliks Kazimierz Potocki, Polish noble and military leader in the late 1600s, Charles Martel, a French military leader from the 700s.

Tarrant also frequently posted links to articles about extremism in Europe, multiculturalism and previous terror attacks.

MULTIPLE DEAD IN MOSQUE SHOOTING

Tarrant livestreamed the shooting to social media, sharing the horrifying video to Facebook.

The distressing footage, viewed by news.com.au and verified by Storyful, shows the gunman walk around the corner and up the path into the Al Noor Mosque. He walks through the front door and opens fire indiscriminately.

The video shows him firing into many rooms with a semiautomatic rifle, leaving bodies strewn on the floor as others run for their lives.

The shooter was active on social media in the days leading up to the attack, posting a photo of the rifle he used two days before the attack.

He also posted photos of the military gear he wore in the attack and the magazines he used to mow down the innocent people.

Police described it as an "evolving situation" and implored residents to stay indoors. All Christchurch schools have been locked down.

It's understood about 300 people were inside the Hagley Park mosque for afternoon prayers when one of the shootings happened. There are reports children were also at the scene and four to five men were seen being led out of the building with their hands behind their head.

New Zealand Police urged anyone in Christchurch to stay indoors and report any suspicious behaviour.